Iron overload affects life of many people in the US and around world. Liver iron concentration provides a direct indication of body iron level. Among various noninvasive methods, Biomagnetic liver susceptometry (BLS) has been proven to provide the only direct means of determining hepatic iron stores. However, BLS requires cost- prohibitive (~ 1 million) and complex (~ 4 K, liquid helium) SQUID magnetometer, which limit the clinic adoption of this technology. The objective of this program is to develop a novel ultra-sensitive piezoelectric magnetic susceptometer for noninvasive liver iron assessment. Among various sensors, piezoelectric sensors offer many attractive features such as ultra-high sensitivity, low cost, and robust operation. However, very weak coupling of these materials to magnetic fields prevent them from been used for magnetic field sensing. Recent advances in the multiferroic materials, especially, the magnetoelectric (ME) composites, create unique opportunity for developing piezoelectric sensors for magnetic field sensing. This program will develop room- temperature-operated, low-cost, compact-size, robust, ultrasensitive magnetic sensors for BLS. In our preliminary study, we also developed a ME sensor with first-order gradiometer and characterized its sensitivity using human-liver size phantom with iron concentration from normal (0.05 mgFe/gliver) to severely overdose (5 mgFe/gliver) in an environment without any magnetic shielding. These results provide compiling evidence for feasibility of the ME-based BLS for liver iron quantification. In Aim 1, we will develop, characterize, and calibrate single element ME-based BLS. In Aim 2, we will develop an array ME-based BLS taking advantage of its compact size. Array BLS will enable characterization of liver iron concentration distribution which would allow for reduction of confounds of comorbid pathologies (e.g. cirrhosis and fibrosis). The BLS technology to be developed in this program is both conventional and disruptive. It is conventional because this technology will adopt the principle of SQUID-base BLS which has been proven to be effective in quantifying LIC. It is disruptive because the technology can lead to breakthroughs in cost and size, which would ultimately allow us to develop a portable Doctor's office or patient bed-side BLS device in the future RO1 applications.